This invention relates to one-piece cable ties and more particularly to such ties having release means for releasing the tie after it has been tightened. One-piece plastic cable ties for bundling a plurality of elongate objects such as wires have come into common use in the last two decades. Such ties typically include a locking head having a toothed locking pawl pivotally mounted and extending into a strap-receiving aperture, and a strap having a series of transverse teeth on one surface thereof for engagement with the pawl. These prior art ties are available in both releasable and non-releasable versions with the former generally having a short lever or tab extending from the pawl beyond the strap exit face of the locking head. In releasing the tie, the strap must be pulled at least a short distance through the locking head in the strap tightening direction to allow the pawl to pivot toward the strap exit face and out of engagement with the strap. Of course, the force required to release the strap is a function of the force previously used in applying the tie.
In one type of prior art releasable cable tie, the lever was somewhat rigid and, after tightening, was positioned adjacent the excess threaded portion of the strap. The user preferably deflected the tail of the strap away from the lever to catch the lever with his fingernail. Examples of such cable ties are disclosed in commonly-assigned U.S. Pat. Nos. 3,667,710 and 3,731,347.
In another type of prior art tie, the release lever was slightly longer and was more supple, being intended for grasping between the fingers. If the user's fingers were wet or oily, such a lever was difficult to grasp effectively. Especially if the cable tie had previously been highly tensioned, the fingers could easily slip off the lever and the user was required to resort to the use of a tool, e.g., a pliers, to release the tie.
A cable tie having a ladder-type strap has recently been proposed, the strap comprising two spaced side rails joined by a plurality of spaced rungs. In contrast to the toothed strap wherein the pawl extended only partially into the strap pass path, the pawl used with a ladder-type strap must extend a greater distance through the strap to effectively engage a rung and could extend well beyond the strap. It will be appreciated that with such greater pawl extension, the strap must be pulled a greater distance in the strap-tightening direction to release the pawl of a tie having a ladder strap. Accordingly, it would be difficult for a pawl having a prior art release lever to be moved sufficiently to release a ladder strap especially if the strap has been applied with a moderately high tension.